Human immunodeficiency virus (HIV) is prone to mutation, which leads to drug resistance. It is known that some compounds are reverse transcriptase inhibitors and effective agents in the treatment of HIV and similar diseases, e.g., azidothymidine or AZT. DPC083, DPC 961, and Efavirenz (Sustiva™) are second generation HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs) with enhanced potency. Efavirenz (Sustiva™) has been approved for the treatment of HIV (Antimicrob. Agents Chemother. 1995, 39, 2602). DPC083 and DPC 961 are under clinical evaluation (Journal of Medicinal Chemistry vol. 43, no. 10, 2000, 2019-2030).
Some methods have been reported for the synthesis of Efavirenz (Sustiva™) (Angew. Chem. Int. Ed. no. 5, 1999, 711-713; Journal of Organic Chemistry vol. 63, no. 23, 1998, 8536-8543), DPC083, and DPC 961. These methods disclose the preparation of DPC 961 by a fractional crystallization or 1,4-diastereoselective addition protocol, both employing an auxiliary (Journal of Organic Chemistry vol. 68, no. 3, 2003, 754-761; Tetrahedron Letter vol. 41, 2000, 3015-3019). Very recently, WO0170707 discloses an asymmetric processe for preparing DPC961 via chiral ligand mediated asymmetric addition. However, in the process, a large amount of excess strong base (lithium alkyl and LHMDS) and excess chiral ligand have been used under very strict condition (−20° C.).